Midrash su Geremia 48:30

“She descended to the threshing floor, and did in accordance with everything that her mother-in-law instructed her” (Ruth 3:6).
“She descended to the threshing floor.” Regarding Moav it is written: “I know his arrogance [evrato], said the Lord, that it is unfounded; his boasts [badav] [have accomplished nothing well-founded]” (Jeremiah 48:30). Rabbi Ḥanina bar Pappa, Rabbi Simon, and the Rabbis – Rabbi Ḥanina said: The conception [iburo] of Moav was not undertaken for the sake of Heaven, but rather for the sake of licentiousness, as it is stated: “Israel was dwelling in Shittim, [and the people began to engage in licentiousness with the daughters of Moav]” (Numbers 25:1). “Did not his descendants do so”²⁰⁶The midrash interprets the word badav to mean descendants. Combined with a more literal translation of the entire phrase, “his boasts have accomplished nothing well-founded” can be alternately translated “did not his descendants do so.” for the sake of licentiousness and not for the sake of Heaven? “His descendants did so” is not stated, but rather, “they did not do so,” – [they did not act] for the sake of Heaven but for the sake of licentiousness. “Israel was dwelling in Shittim, and the people began to engage in licentiousness.” The Rabbis say: The conception of Moav was undertaken for the sake of licentiousness, but ultimately it was for the sake of Heaven, as it is stated: “She descended to the threshing floor, and did [in accordance with everything that her mother-in-law instructed her].”